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You can draw some general conclusions on a quilt's effectiveness based on loft, and this may help you compare one quilt/bag to another...but that's all. So many other factors affect the true temp someone can take a quilt to, and some of them won't even be constant for a person. Hydration level, that day's exertion level, whether you're hungry, how long it's been since you last ate complex carbs, humidity level, wind speed, dew point, price of tea in Thailand, etc.

That's why it's difficult for a manufacturer to give a solid temp rating.

“Republics are created by the virtue, public spirit, and intelligence of the citizens. They fall when the wise are banished from the public councils because they dare to be honest, and the profligate are rewarded because they flatter the people, in order to betray them.” ~Judge Joseph Story

Okay, I am a cold sleeper, and the Hudson River rating is spot on for me. So your own mileage will vary.

If you look at a 20 degree Western Mountaineering sleeping bag, you will see a five inch loft - halve that (it's a sleeping bag, there's a top and bottom) and you get 2.5 inches of loft. The Hudson River and its 3 season JRB brethren have 2.5 inches of loft. Western Mountaineering is one of those brands that needs not exaggerate - it's the Lexus of sleeping bags, by the standards of most reviewers conservatively rated, and like our JRB quilts they use high quality down.

So I would say that if a quilt were adequately filled to 2.5" of down loft, it would likely be capable of the same 20-25F rating easily.

Certainly I have found the JRB Mt.Wash4 to be very conservatively rated simply based on measured loft. Like my PeaPod, mine actually had MORE loft per my measurements than rated. Temp wise, with it's 0-10F rating I can only say I was plenty warm at 10*F, because that's the coldest that conditions available to me so far. Others have taken it below zero, but that gets to the question posed by the OP: what other winter gear was being worn or used? What base layers, etc.

But when it comes to comparing to a Western Mountaineering bags loft AND temp rating, remember the dif in a bag and quilt. First of all, the hood. And I think the Jacks would be the first to say that if you are going to be really warm at 20-25*F in a 2.5" loft quilt, you probably will need a hood to go with it. Just like a sleeping bag. Although, if the quilt is long enough, for side sleeping I am able to produce a faux hood by pulling the quilt over my head and fashioning a small breathing hole.

But above all else, consider draft control, especially for larger folks. That can make or break warmth with a TQ. Zipped up inside that WM 2.5" loft bag with neck collar cinched down tight and hood closed down to a small breathing hole is one thing. Being under a 2.5" loft TQ can be another. Unless the TQ is plenty wide enough for the user ( less of a problem in the hammock), having every thing tucked just right head to toe might be a challenge.

Even if the quilt is big enough for a given sized user, if you move much some new skills will come in handy. It helps to learn to turn over with out causing even a temporary draft which allows your trapped body warmth to escape. It is also important that the quilt can be well secured around the neck and shoulders. I find a "snap" and draw string to be really helpful.

Of course most of us will learn to deal with all of the above for the many other benefits of using a TQ vs a bag in a hammock. But, a 2.5" TQ can not necessarily be directly compared to a 2.5" top loft(5" total) mummy bag in temp rating. It can be if the other variables are taken care of. Just something for a hammock noob to consider.

Similarly, when looking at an UQ and comparing sleeping bag loft/ temp ratings, loft is not the entire story. Fit is critical. Plus, any extra exposure to air flow- on the bottom compared to the top- might need to be considered.

Last edited by BillyBob58; 07-09-2010 at 08:26.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

Also consider how BPL won't even try to confirm a manufacturer's temp ratings, because there are so many variables, for bags or quilts. The closest they come is to carefully measure loft and compare that to the manufacturer's specs. Then they refer to some tables of loft vs warmth for a general guide line, with the understanding of the other many variables in design, conditions and user. Lot's of variables!

For example, if my wife and I were to rate any given piece of gear for warmth, I bet we would vary by 15 or 20 degrees.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

Down thickness can generally be used to 'scientifically' predict body protection at varying temps --- aside from certain construction techniques and body variations.

I am looking for similar guidance related to UQ and TQ combinations/thickness which can readily be used for similar predictions.

I am a relative UQ newbie and hammock in cool weather so that my concern is to have adequate insulation underneath.

I think if "certain construction techniques and body variations." are accounted for, then you can pretty much go by the old standards for prediction.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22

But when it comes to comparing to a Western Mountaineering bags loft AND temp rating, remember the dif in a bag and quilt. First of all, the hood. And I think the Jacks would be the first to say that if you are going to be really warm at 20-25*F in a 2.5" loft quilt, you probably will need a hood to go with it. Just like a sleeping bag. Although, if the quilt is long enough, for side sleeping I am able to produce a faux hood by pulling the quilt over my head and fashioning a small breathing hole.

The Jacks sell a down hood. You can also get a down balaclava from the Down Works; they make very good ones for around seventy bucks. I use a beanie hat and add a fleece balaclava if extreme cold is suspected/expected.

I migrated to quilts from mummy bags because I developed a rather intense dislike for the hoods, so possibly blocked that out as being a factor. I much prefer being able to move my head independently of the body insulation. I would use a hat instead of a hood even if someone forced me into a mummy bag for that reason.

In the winter, one of the layers that I carry/wear is an extreamly light weight down jacket. It's mostly used for camp or when I stop hiking and need insulation at lunch. But at night it's got another use... My hammock is a "Tropical" clark and the head end is more open than the NA version. I will bunch up my down jacket into the head end of my hammock. During the night, this acts as a head warmer, keeping the top of my head nice and toasty. I've also got a weathershield that I close down, except for a small opening at the head end for venting. This weathershield keeps more heat inside my hammock than when I don't use it. And... my underquilt has a waterproof layer on the outside (not the side that's up against my hammock). And my top quilt has a layer of silk sewn to the side that's against me. This silk layer has been extended past the top edge of my quilt so I can use it to cover my face with it. Point I'm trying to make is that... even though my quilts are rated around 5 degrees, I've got extra stuff that changes that. Like the silk layer, I added it because I didn't like the way my top quilt felt. It would get sort of damp feeling, I think because of condensation. The silk completely got rid of that and it adds a little warmth causing me to sleep even better. Putting extra silk on my quilt to cover my face is really nice.
When I started testing my winter under quilt and winter top quilt last year, one of my first nights in it, I slept cold. Figured out that 1, I needed more food and 2, I had an air gap in the under quilt. That night wasn't all that cold, maybe 32, 31 degrees but I learned the importance of having my underquilt fitted to the bottom of my hammock. Since then, I've used the same under quilt down to 20 degrees in falling snow and windy conditions and slept toasty warm. All I had to do was get rid of the air gaps. Testing in the back yard is priceless!!!

The Jacks sell a down hood. You can also get a down balaclava from the Down Works; they make very good ones for around seventy bucks. I use a beanie hat and add a fleece balaclava if extreme cold is suspected/expected.

I migrated to quilts from mummy bags because I developed a rather intense dislike for the hoods, so possibly blocked that out as being a factor. I much prefer being able to move my head independently of the body insulation. I would use a hat instead of a hood even if someone forced me into a mummy bag for that reason.

That's the great thing about an add on hood like the jacks when used with a quilt! The hood moves with your head when you turn over, just like a balaclava would.

For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us....that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. For we know that the whole creation groans and suffers the pains of childbirth together until now.
Romans 8:18,21-22